The National Council on Disability (NCD) undertook this report to increase the understanding of guardianship and its impact on the lives of people with intellectual and developmental disabilities (ID/DD) and their families. Guardianship is the process through which an adult can be found legally incapable of making decisions for him or herself and another adult is appointed to make decisions on behalf of that individual. In this report, NCD examines why people with ID/DD are at increased risk for becoming subject to guardianship as adults, and how that impacts their ability to benefit from civil rights laws aimed at advancing the self-determination and opportunities available to people with ID/DD, including the Americans with Disabilities Act, the Developmental Disabilities Act, the Individuals with Disabilities Education Act, and the Workforce Innovation and Opportunity Act. The report examines how people with ID/DD are treated differently than other adults who are the subjects of guardianship proceedings, including in several states that have separate guardianship laws for people with ID/DD. The findings and recommendations are based on the available data on guardianship for people with ID/DD, an in-depth examination of the experiences of individuals with ID/DD in Washington, DC, and information collected directly from stakeholders across the nation.